1. Field of the Invention
This invention relates to a recyclable polymer which is an advantageous and significant novel material for recycling, a process for producing the same, a method for recovering the same, and a method for regenerating the same. More specifically, this invention is to provide an approach to cope with the disposal of polymeric waste such as shredder residues of scrapped cars.
2. Description of the Related Arts
In recent years, considering the limited resources such as petroleum for use as raw materials and the problem of disposal of wastes, recycling of polymeric materials such as shredder residues of cars and the like have aroused our interest. However, the recycling of polymeric materials has posed problems such as the following:
(1) The mixture of various kinds of polymeric materials contained in waste is difficult to fractionate and recover. PA1 (2) The properties of the polymeric materials deteriorate when they are reused. PA1 (1) The bonding of a linkage unit is a chemical bond which is different from the bonding between monomers, and allows scission and re-bonding by such a predetermined treatment capable of scissoring only the chemical bond in the linkage units. PA1 (2) The presence of a linkage unit does not substantially impair the inherent properties of the polymer.
With respect to the above problem (1), there are two techniques that may be used, namely one in which commingled materials are fractionated based on their solubility in a solvent as disclosed in, e.g., "Chemical Approach to Recycling Mixed Plastics from Shredder Fluff", B. J. Jody, E. J. Daniels, and P. V. Bonsignore in Plast. Recycl. Future Bus. Oppor. 38-46 (1991), and another which involves fractionation based on differences in specific gravity.
Next, with respect to the above problem (2), there is a technique by which a waste of polymeric materials is decomposed into monomers which are then polymerized again to revive their qualities, as disclosed in, e.g., "Thermoplastic Compression Molded Horizontal Automotive Panels", M. D. Drigotas, G. P. Weeks, and J. M. Fisher in SAE Tech. Pap. Ser. (1992).
However, it is hard to fractionate thermosetting resins having poor solubility or resins having close specific gravities using the above-mentioned fractionation techniques. Meanwhile, in the technique of reviving the qualities, the kinds of the polymeric materials that can be decomposed into monomers are limited. Moreover, the polymerization after decomposition to monomers involves a great loss of energy, which is economically disadvantageous.